JPH04161886A - Fuel assembly - Google Patents
Fuel assemblyInfo
- Publication number
- JPH04161886A JPH04161886A JP2285998A JP28599890A JPH04161886A JP H04161886 A JPH04161886 A JP H04161886A JP 2285998 A JP2285998 A JP 2285998A JP 28599890 A JP28599890 A JP 28599890A JP H04161886 A JPH04161886 A JP H04161886A
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- round cell
- fuel rods
- channel box
- rods
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 80
- 125000006850 spacer group Chemical group 0.000 claims description 44
- 238000009835 boiling Methods 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 230000002776 aggregation Effects 0.000 claims 2
- 238000004220 aggregation Methods 0.000 claims 2
- 239000007788 liquid Substances 0.000 abstract description 23
- 230000008719 thickening Effects 0.000 abstract description 2
- 238000003466 welding Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 13
- 230000007704 transition Effects 0.000 description 11
- 230000003287 optical effect Effects 0.000 description 7
- 239000002826 coolant Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 230000005514 two-phase flow Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/34—Spacer grids
- G21C3/344—Spacer grids formed of assembled tubular elements
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/322—Means to influence the coolant flow through or around the bundles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Fuel Cell (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、燃料集合体、特に沸騰水形原子炉用燃料集合
体に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel assembly, particularly a fuel assembly for a boiling water nuclear reactor.
従来、原子炉用の燃料集合体では熱伝達の向上を目的と
したスペーサの構造の改良が行われている。加圧水形の
場合には、例えば特公昭４２−３２３７２号公報に開示
されているように、格子形スペーサに羽根状の突起物を
燃料棒を取り囲む四辺の中央部にそれぞれ１個ずつ設け
た構造になっている。このような構造では、適切な羽根
の位置と形状により、冷却材は燃料棒を覆うように周り
に沿って流れることになる。その結果、冷却材をミキシ
ングさせることになって、熱伝達の向上を図り、炉心の
熱的余裕を増大させている。Conventionally, improvements have been made to the structure of spacers in fuel assemblies for nuclear reactors in order to improve heat transfer. In the case of a pressurized water type, for example, as disclosed in Japanese Patent Publication No. 42-32372, a structure in which a lattice-shaped spacer is provided with one blade-shaped protrusion at the center of each of the four sides surrounding the fuel rod is used. It has become. In such a construction, proper vane position and shape directs the coolant to flow around and over the fuel rods. As a result, the coolant is mixed to improve heat transfer and increase the thermal margin of the core.
しかしながら、上記従来例の技術は、加圧水彩原子炉で
使用するものであり、これを沸騰水形原子炉に適用した
場合には上記の目的を達成することは困難となる。第３
図は沸騰水形原子炉の燃料棒間の冷却材の流動状態を示
す図であり、１は燃料棒、２は液膜、３は液滴である。However, the above conventional technology is used in a pressurized watercolor nuclear reactor, and if it is applied to a boiling water reactor, it will be difficult to achieve the above objective. Third
The figure shows the flow state of coolant between fuel rods of a boiling water reactor, where 1 is a fuel rod, 2 is a liquid film, and 3 is a droplet.
沸騰水形原子炉の燃料集合体では、ボイドの発生により
燃料棒間の冷却材の流動状態は、第３図に示すような二
相流状態となる。すなわち、燃料棒１の表面上に液膜２
流が生じ、燃料棒１間の空間は蒸気と液滴３が混じり合
った流動状態となる。In the fuel assembly of a boiling water reactor, the flow state of the coolant between the fuel rods becomes a two-phase flow state as shown in FIG. 3 due to the generation of voids. That is, a liquid film 2 is formed on the surface of the fuel rod 1.
A flow is generated, and the space between the fuel rods 1 becomes a fluid state in which steam and droplets 3 are mixed.
このような流動状態において、上記従来例に示すような
スペーサを使用すると、冷却材は燃料棒１の周囲を沿う
ような流れとなる。そのため、燃料棒１に付着している
液膜２をはぎ取るような流れとなり、燃料棒１に付着す
る液膜２の量は少なくなる。すなわち、燃料棒１の表面
の液膜２が消滅し沸騰遷移を起こしやすくなる。このた
め、この沸騰遷移時の出力、すなわち限界出力は下がる
ことになる。In such a flow state, if a spacer such as that shown in the conventional example is used, the coolant flows around the fuel rods 1. Therefore, the flow becomes such that the liquid film 2 adhering to the fuel rod 1 is stripped off, and the amount of the liquid film 2 adhering to the fuel rod 1 decreases. That is, the liquid film 2 on the surface of the fuel rod 1 disappears, making boiling transition more likely to occur. Therefore, the output during this boiling transition, that is, the limit output, decreases.
本発明の目的は、上記問題点を解消し、熱的余裕と安定
性に富む燃料集合体を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a fuel assembly with excellent thermal margin and stability.
上記の目的は、次のようにして達成される。 The above objective is achieved as follows.
（１）円筒状の丸セルリングを束ねた構造からなる光セ
ル形スペーサと、丸セルリングにより相互の間隔が保持
される燃料棒と、光セル形スペーサを取り囲む断面が多
角形のチャネルボックスと、チャネルボックスの隣り合
う２側面の各面に、２側面の各面がそれぞれ向い合うよ
うに配設されている制御棒を有する沸騰水形原子炉にお
いて、チャネルボックス内で制御棒から最も離れたコー
ナ部及びその周辺に、旋回流を生じさせるベーンを配設
すること。(1) A photocell spacer consisting of a bundle of cylindrical round cell rings, a fuel rod whose mutual spacing is maintained by the round cell rings, and a channel box with a polygonal cross section surrounding the photocell spacer. , in a boiling water reactor having control rods arranged on each side of two adjacent sides of a channel box so that each side of the two sides faces each other, the area farthest from the control rod in the channel box Arrange vanes that generate swirling flow in and around the corners.
（２Ｈ，Ｌ）において、チャネルボックス内の制御棒か
ら最も離れたコーナ部及びその周辺で、かつ制御棒に面
しない前記チャネルボックスの２側面の内面に最も近い
側にそれぞれ並設してある第１列目の燃料棒とチャネル
ボックスの各内面により囲まれる第１空間内、及び第１
列目の燃料棒と更にこれより１列内側に並設されている
第２列目の燃料棒により囲まわる第２空間内で発生する
Ｍ、滴が遠心力により、第１及び第２の各空間を形成し
ている各燃料棒に向うような旋回流を生じさせるベーン
を設けること。In (2H, L), the channels are arranged in parallel at and around the corner farthest from the control rod in the channel box, and on the side closest to the inner surface of the two side surfaces of the channel box that do not face the control rod. within a first space surrounded by the first row of fuel rods and each inner surface of the channel box;
M droplets generated in the second space surrounded by the row of fuel rods and the second row of fuel rods arranged in parallel one row inside are caused by centrifugal force to cause the first and second rows of fuel rods to flow into each other. Providing vanes that generate a swirling flow toward each fuel rod forming the space.
（３）（１）において２チヤネルボツクス内の制御棒か
ら最も離れたコーナ部及びその周辺で、かつチャネルボ
ックスの制御棒と面しない側面の内面に、燃料棒の長手
方向に対して斜め方向にあたる方向に旋回流発生用のベ
ーンを設けること。(3) In (1), at the corner farthest from the control rod in the 2-channel box and around it, and on the inner surface of the side of the channel box that does not face the control rod, in a diagonal direction with respect to the longitudinal direction of the fuel rod. Provide a vane to generate swirling flow in the direction.
（４）（２）において、第１列目の燃料棒及び第２列目
の燃料棒を保持する各丸セルリングの側面に。(4) In (2), on the side of each round cell ring that holds the first row of fuel rods and the second row of fuel rods.
燃料棒の長手方向に対して斜めにあたる方向に旋回流発
生用のベーンを設けること。A vane for generating swirling flow is provided in a direction oblique to the longitudinal direction of the fuel rod.
（５）（４）において、チャネルボックス内の制御棒か
ら最も離れたコーナ部及びその近くで、丸セルリングを
束ねるサイドバンドの内面に旋回流発生用のベーンを設
けること。(5) In (4), a vane for generating swirling flow is provided on the inner surface of the side band that bundles the round cell rings at and near the corner farthest from the control rod in the channel box.
（６）（４）又は（５）において、旋回流発生用のベー
ンを設けた丸セルリング又はサイドバンドを上から２段
目と３段目の各光セル形スペーサに配設すること。(6) In (4) or (5), a round cell ring or side band provided with a vane for generating a swirling flow is arranged in each of the second and third stages of optical cell type spacers from the top.
（７）（４）において、丸セルリングの一部が隣接する
丸セルリングと長手方向で重畳するような構成にするこ
と。(7) In (4), the structure is such that a part of the round cell ring overlaps an adjacent round cell ring in the longitudinal direction.
沸騰水形原子炉用燃料集合体の二相流領域において、燃
料棒間に旋回流を発生させたときの流動状態を第４図に
示す、第４図において、４は旋回流であり、他は前出の
符号と同一である。燃料棒１にはさまれた空間内に旋回
流４を生じさせることにより、蒸気中に含まれている液
滴３が、旋回流４による遠心力のため、燃料棒１に沿う
液膜２に付着する。したがって、従来に比べて、燃料棒
１の表面の液膜２流の量が増えるため、沸騰遷移に対す
る熱的余裕が増加し、限界出力が向上する。Figure 4 shows the flow state when a swirling flow is generated between the fuel rods in the two-phase flow region of a fuel assembly for a boiling water reactor. is the same as the previous symbol. By generating a swirling flow 4 in the space between the fuel rods 1, droplets 3 contained in the steam form a liquid film 2 along the fuel rods 1 due to the centrifugal force caused by the swirling flow 4. adhere to. Therefore, since the amount of the liquid film 2 flow on the surface of the fuel rod 1 is increased compared to the conventional case, the thermal margin against boiling transition is increased, and the limit output is improved.
上記理由により、丸セルスペーサを形成している丸セル
リングの側面に旋回流発生用のベーンを設けると、燃料
棒１で囲まれる空間内で旋回流４が生じ、熱的余裕を増
加させることができる。旋回流４の強さを増せば熱的余
裕は更に増加し、旋回流４を強めるためには旋回流発生
用のベーンを大きくすればよいが、ベーンを大きくする
ことは圧力損失が増大する結果を招く、シたがって、圧
力損失を増大させずに熱的余裕を増やすことが必要とな
る。For the above reasons, if a vane for generating swirling flow is provided on the side surface of the round cell ring forming the round cell spacer, swirling flow 4 will be generated within the space surrounded by fuel rods 1, increasing the thermal margin. I can do it. If the strength of the swirling flow 4 is increased, the thermal margin will further increase, and in order to strengthen the swirling flow 4, the vane for generating the swirling flow can be made larger, but increasing the size of the vane results in an increase in pressure loss. Therefore, it is necessary to increase the thermal margin without increasing the pressure drop.
しかし、沸騰遷移は全ての燃料棒１で同時に生ずるので
はなく１局所的に生ずるものである。−般に、沸騰遷移
が生じやすい、すなわち出力が高く、熱的に厳しい位置
は制御棒に面しない光セル形スペーサ側面の内面の制御
棒から最も離れたコーナ部及びその周辺の燃料棒１が位
置する領域である。このため、これらの燃料棒１で囲ま
れる空間のみで旋回流４が発生するように光セル形スペ
ーサを構成している丸セルリングの側面にベーンを設け
ると、大きなベーンを使用してもベーンの数が少ないた
めに圧力損失の増加はほとんどなく、逆に大きなベーン
の採用により燃料棒表面に沿って流れる液膜流量が増加
し、熱的余裕が増大する。However, the boiling transition does not occur simultaneously in all fuel rods 1, but only locally. - In general, the locations where boiling transition is likely to occur, that is, where the output is high and which are thermally severe, are the corners of the fuel rods 1 furthest from the control rods on the inner surface of the side surfaces of the optical cell type spacers that do not face the control rods, and the surrounding areas. This is the area where it is located. Therefore, if vanes are provided on the side surfaces of the round cell ring that constitutes the optical cell type spacer so that the swirling flow 4 is generated only in the space surrounded by these fuel rods 1, even if large vanes are used, the vanes Since the number of vanes is small, there is almost no increase in pressure loss, and on the contrary, the adoption of large vanes increases the flow rate of the liquid film flowing along the fuel rod surface, increasing thermal margin.
第５図にベーンの数とスペーサ部における圧力損失との
関係を示すが、ベーンを多数使用するとスペーサ内部に
おける投影面積（スペーサを上から見たときの面積）が
増大するため、スペーサ内部の流路が挾まり圧力損失が
増大する。しかし１本発明の場合は使用するベーンの数
を１５程度以下にすることができるので、圧力損失はほ
とんど増大しないことになる。Figure 5 shows the relationship between the number of vanes and the pressure loss in the spacer. If a large number of vanes are used, the projected area (area when looking at the spacer from above) inside the spacer increases, so the flow inside the spacer increases. The pressure loss increases as the passage gets blocked. However, in the case of the present invention, the number of vanes used can be reduced to about 15 or less, so the pressure loss will hardly increase.
次いで、前記したように、燃料集合体の沸騰遷移の発生
しやすい位置は、制御棒と面しない光セル形スペーサ側
面の内側コーナ近傍であるが、軸方向には上から１段目
と２段目の各光セル形スペーサの上流で発生する。光セ
ル形スペーサは普通は７段前後からなり、光セル形スペ
ーサを形成している各丸セルリングが上下方向に、ある
間隔をおいて７段にわたり、それぞれの燃料棒を保持し
ているが、その最上段近傍において沸騰遷移が発生しや
すい。このことは次のように説明される。Next, as mentioned above, the boiling transition of the fuel assembly is likely to occur near the inner corner of the side surface of the photocell type spacer that does not face the control rods, but in the axial direction, it is located at the first and second stages from the top. Occurs upstream of each photocell-shaped spacer in the eye. A photocell type spacer usually consists of around seven stages, and each round cell ring forming the photocell type spacer spans seven stages vertically at a certain interval, and holds each fuel rod. , boiling transition is likely to occur near the top stage. This is explained as follows.
第６図に燃料棒の軸方向位置と燃料棒表面に沿う液膜厚
さとの関係を示す、光セル形スペーサの配設位置近傍を
除くと、軸の上方に向うにつれて液膜は蒸発して減るこ
とから、液膜厚さは単調に減少する。しかし、光セル形
スペーサの配設位置近傍では、光セル形スペーサにより
流れが乱されることから付着量が増加し、液膜厚さがス
テップ状に変化する。すなわち、１段目と２段目の各光
セル形スペーサの上流で液膜厚さが薄くなるため、出力
を上げると、この位置で沸騰遷移が発生することになる
。しかし、本発明になるベーンの付いた光セル形スペー
サを、液膜厚さの薄い部分に配設すれば液膜厚さが増加
することになる。Figure 6 shows the relationship between the axial position of the fuel rod and the liquid film thickness along the fuel rod surface.Excluding the vicinity of the photocell type spacer, the liquid film evaporates as it moves upward along the axis. Since the liquid film thickness decreases, the liquid film thickness decreases monotonically. However, near the location where the photocell type spacer is disposed, the flow is disturbed by the photocell type spacer, so the amount of adhesion increases and the liquid film thickness changes stepwise. That is, since the liquid film thickness becomes thinner upstream of each of the first and second stage photocell type spacers, if the output is increased, a boiling transition will occur at this position. However, if the vaned photocell type spacer according to the present invention is disposed in a portion where the liquid film thickness is thin, the liquid film thickness will increase.
以下、本発明の一実施例を第１図及び第２図を用いて説
明する。第１図は本実施例を上方から見た場合について
の説明図であり、第２図は同じ〈実施例における丸セル
リングにベーンを設けた場合についての説明図である。An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram of this embodiment when viewed from above, and FIG. 2 is an explanatory diagram of the same embodiment in which a vane is provided on a round cell ring.
第１図及び第２図において、５はチャネルボックス、６
は光セル形スペーサ、７は丸セルリング、８はベーン、
９は制御棒であり、前出のものと同じ部分には同一符号
を付してある。第１図は燃料棒ｌを保持する丸セルリン
グ７が隣接する丸セルリング７と点溶接などによって連
結して束ねられた構造になる光セル形スペーサ６がサイ
ドバンド（図示せず）で束ねられ、チャネルボックス５
内に牧められており、かつ制御棒９に面しないチャネル
ボックス５の側−面の内側に配設してある燃料棒１にベ
ーン８が設けられた状態を示し、第２図は丸セルリング
７にベーン８を設けた状態を示している。゛沸騰水形原
子炉用燃料集合体では１作用の項で説明したように、制
御棒に面しない光セル形スペーサ側面の内側に位置する
燃料棒１近傍の出力が高くなり、熱的には厳しくなる。In Figures 1 and 2, 5 is a channel box, 6
is a light cell type spacer, 7 is a round cell ring, 8 is a vane,
9 is a control rod, in which the same parts as in the previous one are given the same reference numerals. FIG. 1 shows a structure in which a round cell ring 7 holding a fuel rod 1 is connected to an adjacent round cell ring 7 by spot welding or the like and bundled together.A light cell type spacer 6 is bundled with a side band (not shown). channel box 5
Figure 2 shows a state in which vanes 8 are provided on the fuel rods 1 which are arranged inside the side surface of the channel box 5 that does not face the control rods 9. A state in which vanes 8 are provided on the ring 7 is shown. ``In the fuel assembly for a boiling water reactor, as explained in 1. It gets tough.
したがって本実施例では、これらの燃料棒１を保持する
丸セルリング７の側面に、燃料棒１の長手方向に対して
斜めにあたる方向に、第２＠に示すようなベーン８を設
けた。その結果、ベーン８により燃料棒１間の空間に旋
回流が生じ、燃料棒１の表面上の液膜が厚くなって熱伝
達が促進され、限界出力が向上し熱的余裕を増加させる
ことができた。また、ベーン８の取り付は数も少ないた
め、圧力損失の増大はほとんどなかった。ベーン８は簡
単な切り込みにより形成でき、光セル形スペーサ６と一
体構造となるため信頼性の点で優れていることも確めら
れた。なお、第２図に示したベーン８は、三角形状をし
ているが、方形状であっても同様の効果が得られた６更
に、ベーン８は光セル形スペーサ６から独立した部分１
例えばチャネルボックス５の内面に設けても、はぼ同様
の効果が得られた。Therefore, in this embodiment, vanes 8 as shown in the second @ are provided on the side surface of the round cell ring 7 that holds these fuel rods 1 in a direction oblique to the longitudinal direction of the fuel rods 1. As a result, a swirling flow is generated in the space between the fuel rods 1 by the vanes 8, and the liquid film on the surface of the fuel rods 1 becomes thicker, promoting heat transfer, improving the critical output and increasing the thermal margin. did it. Furthermore, since the number of vanes 8 installed was small, there was almost no increase in pressure loss. It has also been confirmed that the vane 8 can be formed by a simple cut and has an integral structure with the photocell type spacer 6, which is excellent in terms of reliability. Although the vane 8 shown in FIG. 2 has a triangular shape, the same effect can be obtained even if the vane 8 has a rectangular shape.
For example, even when it was provided on the inner surface of the channel box 5, similar effects were obtained.
次に、光セル形スペーサ６が燃料棒１の軸方向のどの位
置に配設すればよいか検討した。沸騰遷移の発生しやす
い燃料棒の軸方向の位置については５作用の項で説明し
た０本実施例では光セル形スペーサ６は７段にしており
５上がら２段目と３段目の各光セル形スペーサ６に本発
明を適用すると、光セル形スペーサ６の上端で薄くなっ
ている液膜を厚くする効果が、最小限の数のベーン８の
使用で得られることがわかった。第７図は、２段目と３
段目の各光セル形スペーサ６に本発明を実施したときの
結果を示す、第６図の場合に比べて、液膜厚さが増加し
ており、したがって熱的余裕も増大することがわかった
。Next, we considered where the optical cell spacer 6 should be placed in the axial direction of the fuel rod 1. The axial position of the fuel rod where boiling transition is likely to occur is explained in section 5. It has been found that when the present invention is applied to the cell-shaped spacer 6, the effect of thickening the liquid film that is thin at the upper end of the photocell-shaped spacer 6 can be obtained by using a minimum number of vanes 8. Figure 7 shows the second and third rows.
Compared to the case shown in FIG. 6, which shows the results when the present invention was applied to each photocell type spacer 6 in each stage, it was found that the liquid film thickness has increased, and therefore the thermal margin has also increased. Ta.
このように本実施例では、旋回流発生用のベーンは最小
限に使用しているため、圧力損失はほとんど増大せず、
熱的余裕を大幅に向上させることができたので、この熱
的余裕の増加分を利用して、圧力損失を低下させる方法
について検討した。燃料集合体の圧力損失のうちの２割
は光セル形スペーサ６の部分における損失である。この
光セル形スペーサ６の使用段数を現状の７段から６段に
段数を減らすと、圧力損失は大幅に低減される。しかし
１段数を少なくすると光セル形スペーサ６の設置間隔、
すなわちピッチが長くなり、第８因にスペーサピッチと
限界出力の関係を示すが、これから明らかなように、限
界出力、すなわち沸騰遷移時の出力が低下して、熱的余
裕が／ＪＳさくなる。In this way, in this example, the number of vanes for generating swirling flow is minimally used, so the pressure loss hardly increases.
Since we were able to significantly improve the thermal margin, we investigated ways to reduce pressure loss by utilizing this increased thermal margin. Twenty percent of the pressure loss in the fuel assembly is the loss in the photocell type spacer 6. If the number of stages of the optical cell type spacer 6 used is reduced from the current seven stages to six stages, the pressure loss will be significantly reduced. However, if the number of stages is reduced, the installation interval of the photocell type spacer 6,
That is, the pitch becomes longer, and the eighth factor is the relationship between the spacer pitch and the limit output, and as is clear from this, the limit output, that is, the output at the time of boiling transition, decreases, and the thermal margin decreases by /JS.
しかし、この６段の光セル形スペーサ６に本発明のベー
ンを適用した結果、熱的余裕が向上するために、上記問
題点は解消され、熱的余裕が従来並以上で、かつ圧力損
失を大幅に低減させることができた。However, as a result of applying the vane of the present invention to the six-stage photocell type spacer 6, the thermal margin is improved, so the above problems are solved, the thermal margin is higher than that of the conventional one, and the pressure loss is reduced. We were able to significantly reduce this.
本発明の別の実施例を第９図に示す、第９図における（
ａ）は上部から見た説明図、（ｂ）は要部の説明図であ
る。また、前出と同じ部分には同一符号を付してある１
本実施例は丸セルリング７の一部分が隣接する丸セルリ
ング７と長手方向でオーバラップさせたものであるにの
ため、投影面積が減り、圧力損失が大幅に低減するもの
である。したがって１本実施例を本発明の前出の実施例
におけるベーンと組み合わせた結果、旋回流発生用のベ
ーンは熱的に厳しくなる領域のみに使用するため、圧力
損失を大幅に低減しながら熱的余裕を増加させることが
できた。更に、この熱的余裕を利用して、６段からなる
光セル形スペーサ６に適用して圧力損失を一層低減させ
、安全性を大幅に向上することができた。Another embodiment of the present invention is shown in FIG.
(a) is an explanatory diagram seen from the top, and (b) is an explanatory diagram of the main part. In addition, the same parts as above are given the same reference numerals.
In this embodiment, a portion of the round cell ring 7 overlaps the adjacent round cell ring 7 in the longitudinal direction, so that the projected area is reduced and the pressure loss is significantly reduced. Therefore, as a result of combining this embodiment with the vanes in the previous embodiments of the present invention, the vanes for generating swirling flow are used only in areas that are thermally severe, so that pressure loss can be significantly reduced while thermally I was able to increase my margin. Furthermore, by utilizing this thermal margin, we were able to apply it to a six-stage optical cell spacer 6 to further reduce pressure loss and significantly improve safety.
本発明によれば、燃料棒表面に沿って流れる液膜流量を
増すことができ、これにより熱伝達が促進され、熱的余
裕を増加させる効果が得られる。According to the present invention, it is possible to increase the flow rate of the liquid film flowing along the surface of the fuel rod, thereby promoting heat transfer and achieving the effect of increasing thermal margin.
また、この熱的余裕の増加分を利用して、光セル形スペ
ーサの段数を減らすことにより圧力損失を低減させ、光
セル形スペーサの安定性を改善できる効果も得られる。Further, by utilizing this increased thermal margin and reducing the number of stages of the photocell type spacer, it is possible to reduce pressure loss and improve the stability of the photocell type spacer.
更に、これらの効果的な手段を沸騰遷移の起こしやすい
燃料棒近傍において使用することにより、燃料集合体の
限界出力の向上と安定性に大きく寄与することができる
。Furthermore, by using these effective means in the vicinity of fuel rods where boiling transition is likely to occur, it is possible to greatly contribute to improving the critical output and stability of the fuel assembly.
第１．２図は本発明の一実施例の説明図、第３図は燃料
棒間の冷却材の流動状態の説明図、第４図は燃料棒間に
旋回流を発生させたときの流動状態の説明図、第５図は
旋回流発生用のベーンの使用数とスペーサ部における圧
力損失との関係を示す図、第６図は軸方向の液膜厚さの
解析結果を示す図、第７図は本発明を実施したときの解
析結果を示す図、第８図はスペーサピッチと限界出力と
の関係を示す図、第９図は本発明の別の一実施例の説明
図。
１・・・燃料棒、３・・・液滴、４・・・旋回流、５・
・・チャネルボックス、６・・・光セル形スペーサ、７
・・・丸セルリング、８・・・ベーン、９・・・制御棒
。Fig. 1.2 is an explanatory diagram of one embodiment of the present invention, Fig. 3 is an explanatory diagram of the flow state of coolant between fuel rods, and Fig. 4 is an explanatory diagram of the flow state when a swirling flow is generated between the fuel rods. An explanatory diagram of the state, Figure 5 is a diagram showing the relationship between the number of vanes used for swirling flow generation and pressure loss in the spacer part, Figure 6 is a diagram showing the analysis results of the liquid film thickness in the axial direction, FIG. 7 is a diagram showing the analysis results when the present invention is implemented, FIG. 8 is a diagram showing the relationship between spacer pitch and limit output, and FIG. 9 is an explanatory diagram of another embodiment of the present invention. 1...Fuel rod, 3...Droplet, 4...Swirling flow, 5...
...Channel box, 6...Optical cell type spacer, 7
...Round cell ring, 8...Vane, 9...Control rod.
Claims (1)
形スペーサと、前記丸セルリングにより相互の間隔が保
持される燃料棒と、前記丸セル形スペーサを取り囲む断
面が多角形のチャネルボックスと、前記チャネルボック
スの隣り合う２側面の各面に、２側面の各面がそれぞれ
向い合うように配設されている制御棒を有する沸騰水形
原子炉において、前記チャネルボックス内の前記制御棒
から最も離れたコーナ部及びその周辺に、旋回流を生じ
させるベーンを配設したことを特徴とする燃料集合体。 ２、前記チャネルボックス内の前記制御棒から最も離れ
たコーナ部及びその周辺で、かつ前記制御棒に面しない
前記チャネルボックスの２側面の内面に最も近い側にそ
れぞれ並設してある第１列目の燃料棒と前記チャネルボ
ックスの２側面の各内面により囲まれる第１空間内、及
び前記第１列目の燃料棒と更にこれより１列内側に並設
されている第２列目の燃料棒により囲まれる第２空間内
で発生する液滴が遠心力により、前記第１及び第２の各
空間を形成している各燃料棒に向うような旋回流を生じ
させるベーンを設けてなる請求項１記載の燃料集合体。 ３、前記チャネルボックス内の前記制御棒から最も離れ
たコーナ部及びその周辺で、かつ前記チャネルボックス
の前記制御棒と面しない側面の内面に、前記燃料棒の長
手方向に対して斜めにあたる方向に前記旋回流発生用の
ベーンを設けてなる請求項１記載の燃料集合体。 ４、前記第１列目の燃料棒及び前記第２列目の燃料棒を
保持する各前記丸セルリングの側面に、前記燃料棒の長
手方向に対して斜めにあたる方向に前記旋回流発生用の
ベーンを設けてなる請求項２記載の燃料集合体。 ５、前記チャネルボックス内の前記制御棒から最も離れ
たコーナ部及びその近くで、かつ前記丸セルリングを束
ねるサイドバンドの内面に前記旋回流発生用のベーンを
設けてなる請求項４記載の燃料集合体。 ６、前記旋回発生用のベーンを設けた前記丸セルリング
又は前記サイドバンドを上から２段目と３段目の各前記
丸セル形スペーサに配設してなる請求項４又は５記載の
燃料集合体。 ７、前記丸セルリングの一部が隣接する丸セルリングと
長手方向で重畳する前記丸セル形スペーサで構成される
請求項４記載の燃料集合体。[Claims] 1. A round cell spacer having a structure in which cylindrical round cell rings are bundled, fuel rods whose mutual spacing is maintained by the round cell rings, and a cross section surrounding the round cell spacer. A boiling water nuclear reactor having a channel box having a polygonal shape, and control rods disposed on each of two adjacent side surfaces of the channel box so that the two side surfaces face each other. A fuel assembly characterized in that vanes for generating a swirling flow are disposed at a corner part farthest from the control rod in the box and around the corner part. 2. First rows arranged in parallel at and around the corner farthest from the control rod in the channel box, and on the side closest to the inner surface of the two side surfaces of the channel box that do not face the control rod. a second row of fuel arranged in parallel with the first row of fuel rods and one row further inward from the first row of fuel rods; A claim further comprising a vane that generates a swirling flow such that droplets generated in a second space surrounded by the rods are directed toward each of the fuel rods forming each of the first and second spaces by centrifugal force. The fuel assembly according to item 1. 3. In the corner part farthest from the control rod in the channel box and its surroundings, and on the inner surface of the side surface of the channel box that does not face the control rod, in a direction oblique to the longitudinal direction of the fuel rod. The fuel assembly according to claim 1, further comprising a vane for generating said swirling flow. 4. On the side surface of each of the round cell rings that hold the fuel rods in the first row and the fuel rods in the second row, the swirl flow generating ring is installed in a direction oblique to the longitudinal direction of the fuel rods. 3. The fuel assembly according to claim 2, further comprising a vane. 5. The fuel according to claim 4, wherein the vane for generating swirling flow is provided at and near a corner farthest from the control rod in the channel box and on the inner surface of a side band that bundles the round cell rings. Aggregation. 6. The fuel according to claim 4 or 5, wherein the round cell ring or the side band provided with the swirl generating vane is disposed on each of the round cell spacers in the second and third stages from the top. Aggregation. 7. The fuel assembly according to claim 4, wherein a portion of the round cell ring is constituted by the round cell spacer that overlaps an adjacent round cell ring in the longitudinal direction.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2285998A JP2945459B2 (en) | 1990-10-25 | 1990-10-25 | Fuel assembly |
| US07/782,812 US5272741A (en) | 1990-10-25 | 1991-10-25 | Nuclear fuel assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2285998A JP2945459B2 (en) | 1990-10-25 | 1990-10-25 | Fuel assembly |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04161886A true JPH04161886A (en) | 1992-06-05 |
| JP2945459B2 JP2945459B2 (en) | 1999-09-06 |
Family
ID=17698688
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2285998A Expired - Lifetime JP2945459B2 (en) | 1990-10-25 | 1990-10-25 | Fuel assembly |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US5272741A (en) |
| JP (1) | JP2945459B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004502185A (en) * | 2000-07-03 | 2004-01-22 | ウェスチングハウス アトム アクチボラゲット | Spacers and fuel assemblies for nuclear reactors |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3038266B2 (en) * | 1991-12-09 | 2000-05-08 | 株式会社東芝 | Fuel spacer |
| JP3121972B2 (en) * | 1993-12-03 | 2001-01-09 | 三菱原子燃料株式会社 | Nuclear fuel assembly |
| KR100287278B1 (en) * | 1998-02-04 | 2001-04-16 | 장인순 | Nuclear fuel set supporting grid having rotating mobility generating device |
| SE521687C2 (en) * | 1998-09-18 | 2003-11-25 | Westinghouse Atom Ab | Sprayer and fuel cartridge for a nuclear boiler water reactor |
| US6507630B1 (en) * | 2000-05-01 | 2003-01-14 | General Electric Company | Cell flow diverter and flow diverter/vortex generator assembly for BWR spacers |
| US20050220261A1 (en) * | 2002-02-08 | 2005-10-06 | Framatome Anp Gmbh | Fuel assembly for a boiling water reactor |
| US20080232536A1 (en) * | 2004-01-15 | 2008-09-25 | Westinghouse Electric Sweden Ab | Spacer and a Fuel Unit for a Nuclear Plant |
| JP5585883B2 (en) | 2007-12-26 | 2014-09-10 | トリウム・パワー、インク | Nuclear fuel assembly, light water reactor including nuclear fuel assembly, and method of using nuclear fuel assembly |
| WO2010074592A1 (en) | 2008-12-25 | 2010-07-01 | Ториум Пауэр Инк. | Fuel assembly for a light-water nuclear reactor (embodiments), light-water nuclear reactor and fuel element of the fuel assembly |
| US8116423B2 (en) | 2007-12-26 | 2012-02-14 | Thorium Power, Inc. | Nuclear reactor (alternatives), fuel assembly of seed-blanket subassemblies for nuclear reactor (alternatives), and fuel element for fuel assembly |
| US10170207B2 (en) | 2013-05-10 | 2019-01-01 | Thorium Power, Inc. | Fuel assembly |
| WO2011143172A1 (en) | 2010-05-11 | 2011-11-17 | Thorium Power, Inc. | Fuel assembly with metal fuel alloy kernel and method of manufacturing thereof |
| US10192644B2 (en) | 2010-05-11 | 2019-01-29 | Lightbridge Corporation | Fuel assembly |
| US11087896B2 (en) | 2019-12-10 | 2021-08-10 | Henry Crichlow | High level nuclear waste capsule systems and methods |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3861999A (en) * | 1967-04-14 | 1975-01-21 | Combustion Eng | Nuclear reactor arrangement and method of operating safe effective to increase the thermal amargin in high power density regions |
| US3862000A (en) * | 1972-08-31 | 1975-01-21 | Exxon Nuclear Co Inc | Coolant mixing vanes |
| US3933584A (en) * | 1973-04-23 | 1976-01-20 | Nuclear Fuel Services, Inc. | Grid for nuclear fuel assembly |
| US4021300A (en) * | 1975-05-23 | 1977-05-03 | The United States Of America As Represented By The United States Energy Research And Development Administration | Improved nuclear fuel assembly grid spacer |
| US4539738A (en) * | 1982-09-01 | 1985-09-10 | Westinghouse Electric Corp. | Strap and vane positioning fixture for fuel rod grid and method |
| US4698204A (en) * | 1986-09-17 | 1987-10-06 | Westinghouse Electric Corp. | Intermediate flow mixing nonsupport grid for BWR fuel assembly |
| DE8625662U1 (en) * | 1986-09-25 | 1988-03-03 | Siemens Ag, 1000 Berlin Und 8000 Muenchen, De | |
| DE3824082A1 (en) * | 1987-07-18 | 1989-01-26 | Toshiba Kawasaki Kk | FUEL ARRANGEMENT FOR CORE REACTORS |
| JPH0713664B2 (en) * | 1989-04-26 | 1995-02-15 | 株式会社日立製作所 | Fuel assembly and fuel spacer |
-
1990
- 1990-10-25 JP JP2285998A patent/JP2945459B2/en not_active Expired - Lifetime
-
1991
- 1991-10-25 US US07/782,812 patent/US5272741A/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004502185A (en) * | 2000-07-03 | 2004-01-22 | ウェスチングハウス アトム アクチボラゲット | Spacers and fuel assemblies for nuclear reactors |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2945459B2 (en) | 1999-09-06 |
| US5272741A (en) | 1993-12-21 |
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